Propeller Flashcards
The blade angle is the angle between?
The chord of the blade and the plane of rotation.
Newton’s Third Law states that?
For every action, there is an equal and opposite reaction.
For take-off, the propeller blade must be at ____ pitch?
Fine (low) pitch. A fine pitch allows the engine to reach max speed and hence max power at low speeds.
For cruising / maximum airspeed, the propeller blade should be at a ____ pitch, with a ____ blade angle?
Coarse (high) pitch, with a large blade angle. With a lower engine speed, fuel consumption is reduced, increasing engine efficiency.
The Angle of Attack (AoA) is the angle between?
The chord of the blade and the direction of relative airflow.
The AoA should be ___ degrees to produce Optimum Thrust.
3-4 degrees
To maintain optimum AoA, the blade is?
Twisted from blade root to blade tip with the blade angle being reduced from root to tip.
A propeller experiences what type of stresses?
Bending, tensile and torsional stresses.
The centrifugal twisting force causes the blade to _____ its blade angle.
Decrease
[INFO]
During operation, the constant speed propeller automatically changes its blade angle. During take-off, it has a low blade angle to keep AoA small, maximising power
After take-off, as the speed of the A/C increases, blade angle is increased to reduce fuel consumption.
What are used to generate additional thrust near the fan hub?
Blade cuffs
What changes the angle of the propeller to be in line with the flow of air?
Feathering, which changes the angle of the propeller to be in line with the flow of air, allows for air to flow more smoothly over the propellers of a broken engine, reducing drag, saving fuel and reducing damage to the propellers.
